#!/bin/bash
# SPDX-License-Identifier: MIT

set -e

SELF=${BASH_SOURCE[0]}
SELF_DIR="$( cd "$( dirname "$SELF" )" && pwd )"
source $SELF_DIR/cascading-pr-lib.sh

trap "rm -fr $TMPDIR" EXIT

function repo_login() {
    local repo="$1"
    (
	export DOT=$TMPDIR/$repo
	forgejo-curl.sh logout
	forgejo-curl.sh --token "${options[destination_token]}" login "${options[destination_url]}"
    )
}

function repo_curl() {
    local repo=$1
    shift
    DOT=$TMPDIR/$repo forgejo-curl.sh "$@"
}

function upsert_branch() {
    local repo_api=${options[destination_url]}/api/v1/repos/${options[destination_repo]}
    if repo_curl ${options[destination_repo]} api_json $repo_api/branches/${options[destination_head]} >& /dev/null ; then
	log_info "branch ${options[destination_head]} already exists"
	return
    fi
    repo_curl ${options[destination_repo]} api_json --data-raw '{"new_branch_name":"'${options[destination_head]}'","old_branch_name":"'${options[destination_base]}'"}' $repo_api/branches
    log_info "branch ${options[destination_head]} created"
}

function upsert_pr() {
    local repo_api=${options[destination_url]}/api/v1/repos/${options[destination_repo]}
    local title="cascading-pr from ${options[origin_url]}/${options[origin_repo]}/pulls/${options[origin_pr]}"
    repo_curl ${options[destination_repo]} api --get --data state=open --data type=pulls --data-urlencode q="$title" $repo_api/issues | jq --raw-output .[0]  > $TMPDIR/destination-pr.json
    url=$(jq --raw-output .url < $TMPDIR/destination-pr.json)
    if test "$url" != "null"; then
	log_info "PR already exists $url"
	return
    fi
    repo_curl ${options[destination_repo]} api_json --data-raw '{"title":"'"$title"'","base":"'${options[destination_base]}'","head":"'${options[destination_head]}'"}' $repo_api/pulls > $TMPDIR/destination-pr.json
    url=$(jq --raw-output .url < $TMPDIR/destination-pr.json)
    log_info "PR created $url"
}

function origin_pr_head() {
    local repo_api=${options[origin_url]}/api/v1/repos/${options[origin_repo]}
    repo_curl ${options[origin_repo]} api_json $repo_api/pulls/${options[origin_pr]} > $TMPDIR/origin-pr.json
    jq --raw-output .head.ref < $TMPDIR/origin-pr.json
}

function upsert_clone() {
    local direction=$1 branch=$2 clone=$3

    local fetch=true
    if ! test -d $TMPDIR/$direction; then
	git clone $clone -b $branch $TMPDIR/$direction
	fetch=false
    fi
    (
	cd $TMPDIR/$direction
	if $fetch; then
	    git fetch $direction
	fi
	git config user.email cascading-pr@example.com
	git config user.name cascading-pr
    )
}

function push() {
    local direction=$1 branch=$2 clone=$3

    (
	cd $TMPDIR/$direction
	git add .
	if git commit -m 'cascading-pr update'; then
	    git push --force origin $branch
	    git rev-parse HEAD > ../$direction.sha
	    log_info "pushed"
	else
	    log_info "nothing to push"
	fi
    )
}

function wait_destination_ci() {
    local sha="$1"
    local repo_api=${options[destination_url]}/api/v1/repos/${options[destination_repo]}
    wait_success $repo_api $sha
}

function update() {
    upsert_clone origin ${options[origin_head]} ${options[origin_clone]}
    upsert_clone destination ${options[destination_head]} ${options[destination_clone]}
    (
	cd $TMPDIR/origin
	ls -l  $TMPDIR/destination
	${options[update]} $TMPDIR/destination
    )
    push destination ${options[destination_head]} ${options[destination_clone]}
}

function finalize_options() {
    options[origin_scheme]=$(scheme ${options[origin_url]})
    options[origin_host_port]=$(host_port ${options[origin_url]})
    options[origin_clone]=${options[origin_scheme]}://any:${options[origin_token]}@${options[origin_host_port]}/${options[origin_repo]}
    options[origin_head]=$(origin_pr_head)
    options[destination_scheme]=$(scheme ${options[destination_url]})
    options[destination_host_port]=$(host_port ${options[destination_url]})
    options[destination_clone]=${options[destination_scheme]}://any:${options[destination_token]}@${options[destination_host_port]}/${options[destination_repo]}
    options[destination_base]=${options[destination_branch]}
    : ${options[prefix]:=${options[origin_repo]}}
    options[destination_head]=${options[prefix]}-${options[origin_pr]}
}

function run() {
    dependencies
    repo_login ${options[destination_repo]}
    upsert_branch
    upsert_pr
    repo_login ${options[origin_repo]}
    update
    wait_destination_ci $(cat $TMPDIR/destination.sha)
}

function main() {
    while true; do
	case "$1" in
	    --verbose)
		shift
		verbose
		;;
	    --debug)
		shift
		debug
		;;
	    --origin-url)
		shift
		options[origin_url]=$1
		shift
		;;
	    --origin-repo)
		shift
		options[origin_repo]=$1
		shift
		;;
	    --origin-token)
		shift
		options[origin_token]=$1
		shift
		;;
	    --origin-pr)
		shift
		options[origin_pr]=$1
		shift
		;;
	    --destination-url)
		shift
		options[destination_url]=$1
		shift
		;;
	    --destination-repo)
		shift
		options[destination_repo]=$1
		shift
		;;
	    --destination-token)
		shift
		options[destination_token]=$1
		shift
		;;
	    --destination-branch)
		shift
		options[destination_branch]=$1
		shift
		;;
	    --update)
		shift
		options[update]=$1
		shift
		;;
	    --prefix)
		shift
		options[prefix]=$1
		shift
		;;
	    *)
		finalize_options
		"${1:-run}"
		return 0
		;;
	esac
    done
}

if echo "${@}" | grep --quiet -e '--debug' ; then
    main "${@}"
else
    stash_debug "${@}"
fi